HFCT-based Detection of Partial Discharge Currents on GIS Enclosures

Abstract

This work introduces an approach for partial discharge (PD) detection on GIS that makes use of HFCT. The novelty of this method is that the HFCT is installed at the bolts of the external-type spacers to measure, with a bandwidth in the range of hundreds of MHz, the induced PD surface currents flowing along the GIS compartments. Experiments with calibrator signals were conducted to prove that the PD events induce currents in the compartments and to understand their distribution. Next, measurements with test cells were carried out to estimate the spatial sensitivity of the measuring circuit and the effect of noise and disturbances. Finally, the spectral power ratio clustering technique was applied to test results as a method to discriminate PD and non-PD signals.